Method for producing a pucker-free seam in a garment



United States Patent 3,094,705 METHOD FOR PRODUCING A ER-FREE SEAM IN A GARMENT John 1). Reid and Terrence W. Former, New Grleans, and Julia M. Sloan, Metairie, La., assignors to the United States of America as represented by the Secretary of Agriculture No Drawing. Filed Dec. 29, 1960, Ser. No. 79,468 9 Claims. (Cl. 2-243) (Granted under Title 35, US. Code (H52), sec. 266) A nonexclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

Seam pucker is one of the most serious problems the garment manufacturer and the consumer face in todays wash and wear clothing items. It is believed by many to be due to the difference in shrinkage after washing be tween the thread and the material into which it is sewn. The puckered seams which result spoil the appearance of the garment and negate the wash and wear properties. Seam pucker knows no price bounds; it is present in the cheapest to the highest priced merchandise available.

Much work has been done in an effort to minimize this problem. Garment design has been altered so that less areas are needed to be stitched. Also improvements have been attempted by cutting the garment in the fill or bias direction, using smaller needle and thread size, using larger stitches and fewer to the inch, and using specially made sewing machines with different feeds and needle angle. However, with all these innovations seam pucker is still a serious problem and a constantly increasing one as the consumer demands more and better wash and wear garments.

There is need, therefore, for a process to treat cellulosic thread that would eliminate seam pucker in the garment into which it is sewn yet be suitable for use in the usual high-speed garment sewing machines.

An object of the present invention is to provide a process for treating a cellulosic thread with an essentially monomeric nitrogenous methylol resin in the presence of an acidic, that is, an acid or a latent acid forming metal salt, polymerization catalyst, whereby the impregnated and dried thread can be sewn into the garment followed by pressing to cure the thread in place thus establishing stability and producing a finished garment free from seam pucker.

Another object of the present invention is to provide a process for treating a cellulosic thread with formaldehyde and a mineral acid, such as hydrochloric acid, in an aqueous system thereby not substantially changing the properties of the cellulosic thread, washing out of the unreacted formaldehyde and mineral acid and impregnating the thread with an acidic, that is, an acid or a latent acid forming metal salt, polymerization catalyst, drying the thread, sewing it into garments followed 'by pressing to convert the thread into one which will not cause seam pucker.

Formaldehyde is not used commercially to treat cotton because its reaction is difiicult to control and it volatilizes before it has a chance to react with the cellulose. A more practical approach to the problem of formaldehyde use has been reported by Reeves and coworkers in Textile Research Journal 30, No. 3, 179-192 (1960). It was shown that if the reaction is carried out in an aqueous system problems associated with formaldehyde volatilization, etc., are not present. This treatment carried out in the swollen state gives an unstable thread which will give seam pucker. However, by the use of a second application of an acid or acid forming catalyst, drying the thread, then sewing into garments and pressing, a thread that will eliminate seam pucker will be produced.

Nitrogenous methylol finishing agents suitable for use in the resin treating solution of the process of the present invention include the following modified urea resins, which term is used herein to include methylated methylol ureas and their water soluble lower polymers, as Well as methylol ethylene urea and urea formaldehyde, methylol melamines and methylated methylol melamines, methylol triazone and the like types of resins.

Catalysts suitable for use in the nitrogenous methylol resin treated solution or for use following formaldehyde treatment of the thread include mineral acids (i.e., hydrochloric); organic acids (i.e., maleic, formic); salts (i.e., zinc nitrate, magnesium chloride, ammonium chloride, 2 amino 2 methyl 1 propanol hydrochloride); and mixtures (i.e., zinc nitrate and hydrochloric acid, zinc nitrate and maleic acid, aluminum chloride and magnesium chloride).

The acid catalyst can be incorporated with the nitrogenous methylol resin treatment. However, in the case of the formaldehyde treatment, impregnation of the thread with the acid catalyst must be carried out subsequent to treatment of the thread with the aqueous, acidic, formaldehyde solution. The thread, following treatment for at least about ten minutes in the aqueous, acidic, formaldehyde solution must be washed free of formaldehyde with water and then treated with an aqueous solution containing about 0.5% to 1.0% by weight of the acidic polymerization catalyst.

The thread may be dried subsequent to the Water wash and prior to treatment with the acid polymerization catalyst. The drying step, however, is not essential since the thread, still wet from the water wash, will take up sufiicient catalyst in a single pass through a 0.5 by weight aqueous solution of the acid catalyst to allow an effective cure.

In addition to the nitrogenous methylol resin and cataly'st the aqueous pad bath solution of this invention may also contain wetting agents, softening agents and lubricants such as polyethylene or silicones and other components commonly included in conventional resin treatments. The catalyst pad bath to impregnate the formaldehyde treated thread may also contain wetting agents, softening agents, optical brighteners, and lubricants.

The impregnation of the thread with the aqueous resin pad bath solution or the catalyst impregnation of the formaldehyde treated thread described in this invention, the adjustment to the desired wet pick-up and the drying of the wet thread can be carried out by passing the thread through the solution, removing the excess liquid mechanically and oven, can, or drum drying at a temperature below that at which the curing takes place. A drying temperature of approximately F. is generally preferred. For best results, the dried thread should have a moisture content of approximately 20% by weight. The

add-on or deposit of resin on the thread can be controlled by altering the pad bath concentration and/or squeeze pressure when removing excess liquid to give a specific resin add-on for a particular size, twist, or weight of thread used.

When one must have good seam strength it would be necessary simply to use a stronger thread to start with or put in more stitches per inch and yet not develop seam pucker.

The curing of this dried thread would take place after the garment is manufactured and in the pressing step just prior to packaging. This is a normal operation and hence would not require an additional manufacturing step, however, all seams must be pressed thoroughly to get the full benefit of this invention. The garment press temperature should be between 270 F. and 400 F. for a period of about 30 seconds to about 3-0 minutes, the time depending on the temperature used and the Weight of the particular thread. The longer times are used with the lower curing temperatures.

It is advisable to subject the finished pressed garment to an oven after cure to further cure the resin or formaldehyde in place to impart optimum seam smoothness after laundering. This could be done by passing the carefully hung garments through a tunnel of infrared lamps or the like in the range of about 270 F. to 400 F. for a period of about 3-0 seconds to 4 hours, the time depending on the temperature employed and the weight of the particular thread. The longer time is used with the lower curing temperature.

The treated dried thread should be used on both the top and bottom members of the seam to obtain optimum results.

The following examples illustrate the invention. All proportions in the examples are in terms of weight.

Example 1 Number 50 mercerized thread was treated with 7% dimethylol ethylene urea and 0.5 zinc nitrate, dried at 60 C. for 7 minutes, then sewn into dimethylol ethylene urea resin treated fabric, on a home type sewing machine. The seams were then hand ironed and washed. Excellent results with no seam pucker, were obtained in both the warp and fill direction and this rating was not changed after 6 washes.

1.8% by weight of bound resin was present in the thread. This figure was obtained by curing a section of the resin treated thread, washing with water to remove any unreacted resin and determining the amount of resin present by nitrogen analysis. Dimethylol ethylene urea resin treated fabric was used in this example; however, the process could utilize fabric stabilized with any resin, chemical modification or made from synthetic fiber. Likewise any conventional textile resin, dimethylol ethylene urea, urea formaldehyde, dimethylol ethyl triazone, etc., could be used to treat the sewing thread and not necessarily employing the same resin that is on the fabric.

Example 2 Number 50 mercerized cotton thread was treated with 16% dimethylol ethylene urea, 1% zinc nitrate and 0.1% wetting agent, spun to a wet pickup of 73% and oven dried at 60 C. for 7 minutes. 2.4% by weight of bound resin was present in the thread. This thread and its counterpart, an original untreated thread, were used to sew two pockets of dimethylol ethylene urea treated material on to dimethylol ethylene urea treated material, followed by pressing to cure the thread in place. Commercial sewing machines sewing at 5,000 stitches per minute were used. Although both threads were sewn under the same tension, there was noticeable diiference between the smooth appearance of the pocket sewn with the dried treated thread, and the usual poor appearance of the untreated thread.

Example 3 Mercerized 0000 two cord cotton thread was treated with various percentages of dimethylol ethylene urea,

0.5 zinc nitrate and 1.5% polyethylene softener. The wet pickup was adjusted to 70% and the thread was dried at 60 C. for 7 minutes and stored for 2 months. At this time, single seams were sewn into urea formaldehyde resin treated cotton cloth using commercial sewing machines. The seams were pressed, washed, tumbled dry and evaluated.

Dimethylol ethylene urea Seam pucker- Stiches after 6 washper inch lugs and tumble Pad Bound in dryings bath, thread, percent percent 0 14. Definite. 1 0.2 14 D0. 3 0. 6 14 Do. 5 1. 1 14 Very slight. 7 1. 8 14 None. 7 1.8 18 Very slight. 10 2. 1 14 Do.

Example 4 Seam pucker Percent Catalyst type Chemical after 6 washbound ings and tumble resin dryings Acid forming metal 0.5% zinc nitrate Very little..... 1. 7

salt. hexahydrate.

Do 0.5% magnesium chlo- None 1. 5

ridehexahyclrate. Organic acid 1.0% malcic acid 1. 8 Amine hydrochloride 1.0% 20 amino 2 1. 8

methyl 1 propanol hydrochloride. Ammonium salts 1.0373 ammonium chlo- 1. 8

r e. Inorganic acid 0.05%ahydroohloric 1. 7

am Acid forming metal 0.5% zinc nitrate hex- Very slight 1. 7

salt and an inornhydrate and 1.0% ganlc acid. boric acid. Acid forming metal 0.5% zinc nitrate hex- None 1. 7

salt and an organic ahydrate and 1.0% acid. maleic acid. Untreated thread (control) Defini Example 5 Seam pucker Percent Resin used after 6 washings bound and tumble resin dryings 7% methylated methylol melamine None 2. 0 7% urea formaldehyde 6 3 7% dimethylol ethyl triazone Untreated 0000 thread (control) Example 6 Various thread sizes mercerized and not mercerized were treated with 7% dimethylol ethylene urea, 1.5% polyethylene softener and 0.5% zinc nitrate hexahydrate, the wet pickup adjusted to 70%, and the threads dried at 60 C. for 7 minutes. After storing for 2 months, single seams were sewn into urea formaldehyde resin treated cotton cloth using commercial sewing machines followed by pressing the seams, washing, tumble drying, and evaluating for seam pucker.

Example 7 Mercerized cotton 50 6-cord thread was treated with 7% dimethylol ethylene urea, 0.5% zinc nitrate hexahydrate and 1.5% polyethylene softener and dried at 60 C. for 7 minutes. 1.8% by weight of bound resin was present in the thread. It was stored for a year and a half and then single seams were sewn warpwise as this direction gives the most seam pucker into dimethylol ethyl triazone resin treated cotton cloth using commercial sewing machines. The seams were pressed with a hot iron, washed, tumble dried and evaluated for seam pucker. After 6 washings and tumble dryings no seam pucker was present thus indicating an extended shelf life of thread treated by this process.

Example 8 Two skeins of mercerized 0000 two cord thread was treated with 7.4% solids formaldehyde and 19.5% hydrochloric acid in an aqueous system for minutes at room tempenature, followed by a thorough washing. One skein so treated was then impregnated in a solution of 0.5% zinc nitrate hexahydrate and dried, the other skein was not given the catalyst impregnation. The thread was stored for 1 month, then sewn into dimethylol ethylene urea resin treated cloth and pressed.

The formaldehyde treated catalyst impregnated thread gave no seam pucker after 1, 3, and 6 washings and tumble dryings. However, the formaldehyde treated cotton thread not catalyst impregnated gave definite objectionable pucker after the first wash with no change in appearance after the third and sixth washings.

Example 9 Mercerized 0000 cotton two cord thread was treated with 7.4% solids formaldehyde and 19.5% hydrochloric acid in an aqueous system for 10 minutes at room temperature followed by a thorough washing. Diiierent samples of the thread so treated were then impregnated with various types of catalyst, dried at 60 C. for 7 minutes and stored for 2 months. After time single seams were sewn into urea formaldehyde resin treated cotton cloth, pressed to set the thread in place, washed and tumble dried.

Seam pucker Catalyst type Chemical after 6 washings and tumble dryings Acid forming metal salts. 1.0% magnesium chloride None.

hexahydrate. Organic acid 1.0% maleic acid Do. Inorganic acid 0.05% hydrochloric acid. Do. Ammonium salts 1.0% ammonium chloride. Do. Amine hydrochloride 1.0% 2 amino 2 methyl 1 D0.

propanolhydrochloride. Acid forming metal salt 0.5% zinc nitrate hexahy- Do.

and an organic acid. drage and 0.5% maleic ac1 Acid forming metal salt 0.5% zinc nitrate hexahy- Do.

and an inorganic acid. drate and 0.05% hydrochloric acid. Foiimaldehyde treated 0000 thread not giventhe catalyst Definite.

s ep.

We claim:

1. A method for producing a ucker-free seam in a garment comprising treating a cellulosic thread with a solution containing an essentially monomeric nitrogenous methylol resin and an acidic polymerization catalyst to impregnate the thread with the resin, drying the resinimpregnated thread at a temperature below the curing temperature of the resin, sewing the dried, resin-impregnated thread into a garment of the wash-wear type which has been previously resinified with a nitrogenous methylol resin, and pressing the thus-sewed garment in the area of the sewed thread at a temperature of about from 270 to 400 F. for about from 30 seconds to 4 hours, the longer time being employed with the lower temperature, to cure the thread in place in the garment, thereby to produce a finished garment characterized in that it is free from seam pucker after washing.

2. The method of claim 1 wherein the nitrogenous methylol resin employed to treat the cellulosic thread is selected from the group consisting of dimethylol ethylene urea, methylated methylol melamine, urea formaldehyde, and dimethylol ethyl triazone.

3. The method of claim 1 wherein the nitrogenous methylol resin with which the garment has been previously resinified is selected from the group consisting of dimethylol ethylene urea, urea formaldehyde, and dimethylol ethyl tn'azone.

4. The method of claim 1 wherein the acidic polymerization catalyst is selected from the group consisting of hydrochloric acid, maleic acid, zinc nitrate hexahydrate, magnesium chloride hexahydrate, ammonium chloride, 2-amino-2-methyl-1-propanol hydrochloride, a mixture of zinc nitrate hexahydrate and hydrochloric acid, a mixture of zinc nitrate hexahydrate and boric acid, and a mixture of zinc nitrate hexahydrate and maleic acid.

5. The method of claim 1 wherein the drying of the resin-impregnated thread at a temperature below the curing temperature of the resin is carried out until the moisture content of the thread is aproxirnately 20% by weight.

6. A method for producing a Pucker-free scam in a garment comprising treating a cellulosic thread with an aqueous solution containing formaldehyde and a mineral acid for at least about 10 minutes, washing the thus-treated thread with water until it is free of unreacted formaldehyde, impregnating the washed thread with an aqueous solution containing about 0.5 to 1.0 percent by weight of an acidic polymerization catalyst, drying the thus-impregnated thread at a temperature below F., sewing the thus-dried thread into a garment of the wash-wear type which has been previously resinified with a nitrogenous methylol resin, and pressing the thus-sewed garment in the area of the sewed thread at a temperature of about from 270 to 400 F. for about from 30 seconds to 4 hours, the longer time being employed with the lower temperature, to cure the thread in place in the garment, thereby to produce a finished garment characterized in that it is free from seam pucker after washing.

7. The method of claim 6 wherein the nitrogenous "7 methylol resin with which the garment has been previously resinified is selected from the group consisting of dirri'ethylo'l ethyleneure'a and urea formaldehyde.

;8. The l'nethod of claim 6 wherein the acidic polymerization catalyst is selected from the group consisting of hydrochloric acid, maleic acid, zinc nitrate hexahydrate, magnesium chloride hexahydr'ate, ammonium chloride, 2-arnino-2-metliyl-l propanol hydrochloride, fa mixture of zinc nitrate hexahydr'ate and hydrochloric acid, a mixture of zinc nitrate h'eXahydrate and boric acid, and a mixture of: zinc nitrate hexahydr'ate a'ndmaleic acid.

9. The method of claifn 6 wherein the drying of the impregnated thread at a temperature below 140 F. is carried out until the moisture content of the thread is a1if roiiiniat1y 20% liydiveight.

UNITED STATES PATENTS 2,925,642 Pfefier' Feb. 23, 1960 2,937,380 Reese -May 24, 1960 2,950,553 Hurwitz Augf30, '1960 2,974,432 Warnock et al Mar. 14, 1961 3,025,622 Hilton Mar. 20, 1962 

1. A METHOD FOR PRODUCING A PUCKER-FREE SEAM IN A GARMENT COMPRISING TREATING A CELLULOSIC THREAD WITH A SOLUTION CONTAINING AN ESSENTIALLY MONOMERIC NITROGENOUS METHYLOL RESIN AND AN ACIDIC POLYMERIZATION CATALYST TO IMPREGNATE THE THREAD WITH THE RESIN, DRYING THE RESINIMPREGNATED THREAD AT A TEMPERATURE BELOW THE CURING TEMPERATURE OF THE RESIN, SEWING THE DRIED, RESIN-IMPREGNATED THREAD INTO A GARMENT OF THE WASH-WEAR TYPE WHICH HAS BEEN PREVIOUSLY RESINIFIED WITH A NITROGENOUS METHYLOL RESIN, AND PRESSING THE THUS-SEWED GARMENT IN THE AREA OF THE SEWED THREAD AT A TEMPERATURE OF ABOUT FROM 270* TO 400*F. FOR ABOUT FROM 30 SECONDS TO 4 HOURS, THE LONGER TIME BEING EMPLOYED WITH THE LOWER TEMPERATURE, TO CURE THE THREAD IN PLACE IN THE GARMENT, THEREBY TO PRODUCE A FINISHED GARMENT CHARACTERIZED IN THAT IT IS FREE FROM SEAM PUCKER AFTER WASHING. 